People are growing increasingly dependent on portable electronic devices such a cellular phones, personal computers, digital assistants, car locking controls, electronic watches, calculators, digital cameras, and the like. Because these devices are usually small, they are easily misplaced or forgotten, and because access to these devices is often essential, it is desirable to provide methods and apparatus for insuring that these devices are available when they are needed.
The functionality of both portable and fixed electronic devices is expected to be dramatically extended and improved by the advent of improved short range wireless connectivity provided by Bluetooth™ radio transmitters which are being incorporated into new electronic devices. The Bluetooth radio is built into a small microchip and operates within a globally available frequency band. The Bluetooth specification defines two power levels: a lower power mode with a range of about 10 meters for covering a personal area within a room, and a higher power level with a range of about 100 meters covering a larger area, such as a home or office. Software controls and identity coding built into each microchip ensure that only those units preset by their owners can communicate, and provide a mechanism for identifying other devices that are within range. As discussed below, this new technology may also be used to insure that needed devices are available when they are needed, and to provide related functions.
Other systems can be used to identify particular objects that are within a predetermined range of other objects. For example, identification tags which can be detected at short range are used in electronic article surveillance systems to prevent shoplifting and theft, warehousing and inventory control systems, article processing and inspection systems, and the like. To provide standards for one important class of identification tags, the EPC (Electronic Product Code) has been proposed to as a standard way of designating products, and packaging for products, in a range of retail supply chain application from “backroom” applications such as pallet and carton tracking to “selling floor” applications such as item level tagging.